As the government reviews how an alleged terrorist was able to bring a bomb onto a U.S.-bound plane and try to blow it up on Christmas Day, the Transportation Security Administration is going after bloggers who wrote about a directive to increase security after the incident.

TSA special agents served subpoenas to travel bloggers Steve Frischling and Chris Elliott, demanding that they reveal who leaked the security directive to them. The government says the directive was not supposed to be disclosed to the public.

accidentally posted their procedures guide on the net, and while the secret parts were blacked out, there are software programs that can help people with nefarious intent to see under those “black marks.”